Epoxy resin composition and cured article thereof, semiconductor encapsulation material, novel phenol resin, and novel epoxy resin

ABSTRACT

The object of the present invention is to provide an epoxy resin composition capable of realizing low dielectric constant and low dielectric dissipation factor, which is suited for use as a latest current high-frequency type electronic component-related material, without deteriorating heat resistance during the curing reaction. A phenol resin, which has the respective structural units of a phenolic hydroxyl group-containing aromatic hydrocarbon group (P) derived from phenols, an alkoxy group-containing condensed polycyclic aromatic hydrocarbon group (B) derived from methoxynaphthalene and a divalent hydrocarbon group (X) such as methylene and also has a structure represented by —P—B—X— wherein P, B and X are structural sites of these groups in a molecular structure, is used as a curing agent for the epoxy resin, or a phenol resin as an epoxy resin material.

TECHNICAL FIELD

The present invention relates to an epoxy resin composition which isexcellent in heat resistance, dielectric characteristics and curabilityduring the curing reaction of the resulting cured article and can besuited for use in applications such as semiconductor encapsulationmaterials, printed circuit boards, coating materials and castings, andto a cured article thereof, a novel phenol resin and a novel epoxyresin.

BACKGROUND ART

An epoxy resin composition containing an epoxy resin and a curing agentthereof as essential components are widely used in electronic andelectric components such as semiconductor encapsulation materials andprinted circuit boards, conductive adhesives such as conductive pastes,other adhesives, matrixes for composite materials, coating materials,photoresist materials and developing materials because of excellentvarious physical properties such as heat resistance, moisture resistanceand low viscosity.

In these various applications, particularly advanced materials, it hasrecently been required to further improve performances typified by heatresistance and moisture resistance. For example, in the field ofsemiconductor encapsulation materials, a reflow treatment temperatureincreased due to shift to surface mounting packages such as BGA and CSPand correspondence to lead-free solders, and thus electronic componentencapsulation resin materials having excellent moisture solderingresistance are more required than before.

As the technique for producing electronic component encapsulation resinmaterials which meet such requirements, for example, there is known atechnique in which fluidity is improved by using, as a curing agent forepoxy resin, a methoxy group-containing phenol resin obtained bymethoxylating a phenolic hydroxyl group in a resol resin and convertingthe methoxylated resol resin into a novolak resin in the presence of anacid catalyst and also proper flexibility is imparted to the curedarticle, and thus moisture resistance and impact resistance of the curedarticle itself are improved (see, for example, Japanese UnexaminedPatent Application, First Publication No. 2004-10700).

However, such a curing agent for epoxy resin is inferior in heatresistance because of small number of functional groups per molecule. Inthe field of electronic components, it is of urgent necessity to developa high-frequency device capable of coping with higher frequency andmaterials having low dielectric constant and low dielectric dissipationfactor are required to electronic component-related materials such assemiconductor encapsulation materials. The cured article obtained byusing the methoxy group-containing phenol resin as the curing agent forepoxy resin has less crosslink points and therefore dielectriccharacteristics are improved to some extent, however, dielectricconstant and dielectric dissipation factor do not attain the level whichhas recently been required.

As described above, in the field of electronic component-relatedmaterials, there has never been obtained an epoxy resin compositioncapable of coping with recent higher frequency without causingdeterioration of heat resistance.

DISCLOSURE OF THE INVENTION

Therefore, an object to be attained by the present invention is toprovide an epoxy resin composition capable of realizing low dielectricconstant and low dielectric dissipation factor, which is suited for useas a latest high frequency type electronic component-related material,without deteriorating heat resistance during the curing reaction and acured article thereof, a novel epoxy resin which impart theseperformances, and a novel phenol resin.

The present inventors have intensively studied so as to attain the aboveobject and found that the dielectric constant and the dielectricdissipation factor can be remarkably decreased while maintainingexcellent heat resistance by introducing an alkoxynaphthalene structureinto a phenol novolak resin or novolak type epoxy resin skeleton, andthus the present invention has been completed.

The present invention relates to an epoxy resin composition(hereinafter, this epoxy resin composition is abbreviated to “epoxyresin composition (I)”) including an epoxy resin and a curing agent asessential components, wherein the curing agent is a phenol resin whichhas the respective structural units of:

a phenolic hydroxyl group-containing aromatic hydrocarbon group (P),

an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and

a divalent hydrocarbon group (X) selected from methylene, an alkylidenegroup and an aromatic hydrocarbon structure-containing methylene group,and the phenol resin has, in a molecular structure, a structure in whichthe phenolic hydroxyl group-containing aromatic hydrocarbon group (P)and the alkoxy group-containing condensed polycyclic aromatichydrocarbon group (B) are bonded via the divalent hydrocarbon group (X)selected from methylene, the alkylidene group and the aromatichydrocarbon structure-containing methylene group.

Also the present invention relates to an epoxy resin cured articleobtained by curing epoxy resin composition (I).

Also the present invention relates to a novel phenol resin, includingthe respective structural units of:

a phenolic hydroxyl group-containing aromatic hydrocarbon group (P),

an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and

a divalent hydrocarbon group (X) selected from methylene, an alkylidenegroup and an aromatic hydrocarbon structure-containing methylene group,wherein the phenol resin has, in a molecular structure, a structure inwhich the phenolic hydroxyl group-containing aromatic hydrocarbon group(P) and the alkoxy group-containing condensed polycyclic aromatichydrocarbon group (B) are bonded via the divalent hydrocarbon group (X)selected from methylene, the alkylidene group and the aromatichydrocarbon structure-containing methylene group, and the phenol resinhas a melt viscosity at 150° C., as measured by an ICI viscometer, of0.1 to 5.0 dPa·s and a hydroxyl group equivalent of 120 to 500 g/eq.

Also the present invention relates to an epoxy resin composition(hereinafter, this epoxy resin composition is abbreviated to “epoxyresin composition (II)”) including an epoxy resin and a curing agent asessential components, wherein the epoxy resin has the respectivestructural units of:

a glycidyloxy group-containing aromatic hydrocarbon group (E),

an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and

a divalent hydrocarbon group (X) selected from methylene, an alkylidenegroup and an aromatic hydrocarbon structure-containing methylene, andthe epoxy resin has, in a molecular structure, a structure in which theglycidyloxy group-containing aromatic hydrocarbon group (E) and thealkoxy group-containing condensed polycyclic aromatic hydrocarbon group(B) are bonded via the methylene group (X).

Also the present invention relates to a novel epoxy resin, including therespective structural units of:

a glycidyloxy group-containing aromatic hydrocarbon group (E),

an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and

a divalent hydrocarbon group (X) selected from methylene, an alkylidenegroup and an aromatic hydrocarbon structure-containing methylene group,wherein the epoxy resin has, in a molecular structure, a structure inwhich the glycidyloxy group-containing aromatic hydrocarbon group (E)and the alkoxy group-containing condensed polycyclic aromatichydrocarbon group (B) are bonded via the methylene group (X), and theepoxy resin has a melt viscosity at 150° C., measured by an ICIviscometer, of 0.1 to 5.0 dPa·s and an epoxy group equivalent of 200 to500 g/eq.

Also the present invention relates to a semiconductor encapsulationmaterial, including epoxy resin composition (I) or (II) which furthercontains, in addition to the epoxy resin and the curing agent, aninorganic filler within a range of 70 to 95% by mass with respect to theepoxy resin composition.

According to the present invention, there can be provided an epoxy resincomposition capable of realizing low dielectric constant and lowdielectric dissipation factor, which is suited for use as a latesthigh-frequency type electronic component-related material, whilemaintaining excellent heat resistance of a cured article and a curedarticle thereof, a novel phenol resin which imparts these performances,and a novel epoxy resin.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing a GPC chart of a phenol resin obtained inExample 1.

FIG. 2 is a graph showing a ¹³C-NMR spectrum of a phenol resin obtainedin Example 1.

FIG. 3 is a graph showing a mass spectrum of a phenol resin obtained inExample 1.

FIG. 4 is a graph showing a GPC chart of a phenol resin obtained inExample 2

FIG. 5 is a graph showing a ¹³C-NMR spectrum of a phenol resin obtainedin Example 2.

FIG. 6 is a graph showing a mass spectrum of a phenol resin obtained inExample 2.

FIG. 7 is a graph showing a GPC chart of a phenol resin obtained inExample 3.

FIG. 8 is a graph showing a GPC chart of a phenol resin obtained inExample 4.

FIG. 9 is a graph showing a GPC chart of a phenol resin obtained inExample 5

FIG. 10 is a graph showing a GPC chart of a phenol resin obtained inExample 6.

FIG. 11 is a graph showing a GPC chart of a phenol resin obtained inExample 7.

FIG. 12 is a graph showing a GPC chart of a phenol resin obtained inExample 8.

FIG. 13 is a graph showing a GPC chart of an epoxy resin obtained inExample 9.

FIG. 14 is a graph showing a ¹³C-NMR spectrum of an epoxy resin obtainedin Example 9.

FIG. 15 is a graph showing a mass spectrum of an epoxy resin obtained inExample 9.

FIG. 16 is a graph showing a GPC chart of an epoxy resin obtained inExample 10.

FIG. 17 is a graph showing a ¹³C-NMR spectrum of an epoxy resin obtainedin Example 10.

FIG. 18 is a graph showing a mass spectrum of an epoxy resin obtained inExample 10.

FIG. 19 is a graph showing a GPC chart of an epoxy resin obtained inExample 12.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be described in detail.

Epoxy resin composition (I) of the present invention includes an epoxyresin and a curing agent as essential components, wherein the curingagent is a phenol resin which has the respective structural units of aphenolic hydroxyl group-containing aromatic hydrocarbon group (P), analkoxy group-containing condensed polycyclic aromatic hydrocarbon group(B), and a divalent hydrocarbon group (X) selected from methylene, analkylidene group and an aromatic hydrocarbon structure-containingmethylene group, and which also has, in a molecular structure, astructure in which the phenolic hydroxyl group-containing aromatichydrocarbon group (P) and the alkoxy group-containing condensedpolycyclic aromatic hydrocarbon group (B) are bonded via the divalenthydrocarbon group (X) selected from methylene, the alkylidene group andthe aromatic hydrocarbon structure-containing methylene group.

That is, the phenol resin essentially includes a structural siterepresented by the following structural site A1:

—P—X—B—  [Chemical Formula 1] A1

wherein P is a structural unit of the phenolic hydroxyl group-containingaromatic hydrocarbon group (P), B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the divalent hydrocarbon group (X)(hereinafter each group is abbreviated to “methylene group (X)” or thelike) selected from methylene, the alkylidene group and the aromatichydrocarbon structure-containing methylene group, in a molecularstructure.

In the present invention, because of such characteristic chemicalstructures, an aromatic content in the molecular structure increases,and excellent heat resistance is exhibited. Since a crosslink point in acured article exists in the vicinity of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group (B), it is possible toreduce an adverse influence such as decrease in the dielectric constantand dielectric dissipation factor caused by a secondary hydroxyl groupproduced during curing, and thus excellent dielectric characteristicscan be exhibited. It is worthy of special mention to exhibit excellentdielectric characteristics while introducing a functional group havingcomparatively high polarity such as alkoxy group.

The phenolic hydroxyl group-containing aromatic hydrocarbon group (P)can have various structures, and is preferably a phenol or naphtholrepresented by any one of the following structural formulas P1 to P16,or an aromatic hydrocarbon group formed from the phenol or the naphtholthereof, having an alkyl group as a substituent on the aromatic ringbecause of excellent dielectric performances.

When each of these structures is located at the molecular end, amonovalent aromatic hydrocarbon group is formed. Regarding those havingat least two bonding sites with the other structural site on thenaphthalene skeleton among these structures, these bonding sites mayexist on the same or different nucleus.

Among the phenolic hydroxyl group-containing aromatic hydrocarbon groups(P) described above in detail, those having a methyl group as asubstituent on the aromatic ring can impart excellent flame retardancyto an epoxy resin cured article itself, and it becomes possible todesign a halogen-free material which has highly been required in thefield of electronic components, recently.

Furthermore, the phenolic hydroxyl group-containing aromatic hydrocarbongroups (P) having a methyl group at the ortho-position of the phenolskeleton typified by those represented by the structural formulas P6,P7, P8 and P9 are preferable because a remarkable effect of improvingheat resistance and dielectric characteristics of the cured article isexerted.

The alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B) contained in the phenol resin structure is a monovalent orpolyvalent aromatic hydrocarbon group having an alkoxy group as asubstituent on the condensed polycyclic aromatic ring, and specificexamples include alkoxynaphthalene type structures represented by thefollowing structural formulas B1 to B15, or alkoxyanthracene representedby the following structural formula B16.

When each structure is located at the molecular end, a monovalentaromatic hydrocarbon group is formed. Among the structures describedabove, the bonding site of those having at least two bonding sites withthe other structural site on the naphthalene skeleton may exist on thesame or different nucleus.

Among the alkoxy group-containing condensed polycyclic aromatichydrocarbon groups (B) described above in detail, those having analkoxynaphthalene type structure are preferable because the epoxy resincured article is excellent in heat resistance. Aromatic hydrocarbongroups formed from naphthalene structures having a methoxy group or anethoxy group as a substituent typified by those represented by thestructural formulas B1 to B13, and a structure further having a methylgroup as a substituent are preferable because the epoxy resin curedarticle is excellent in flame retardancy and it becomes possible todesign a halogen-free material which has highly been required in thefield of electronic components, recently.

Examples of the divalent hydrocarbon group (X) selected from methylene,alkylidene group and aromatic hydrocarbon structure-containing methylenegroup contained in the phenol resin structure include, in addition tomethylene, alkylidene group such as ethylidene group, 1,1-propylidenegroup, 2,2-propylidene group, dimethylene group, propane-1,1,3,3-tetraylgroup, n-butane-1,1,4,4-tetrayl group or n-pentane-1,1,5,5-tetraylgroup. Examples of the aromatic hydrocarbon structure-containingmethylene group include those having structures represented by thefollowing formulas X1 to X9.

Among these groups, methylene is particularly preferable because ofexcellent dielectric effect.

The phenol resin used in the present invention can employ anycombination of the structures shown in the respective specific examplesof the structural sites (P), (B) and (X). As described above, themolecular structure of the phenol resin composed of each structural sitehas essentially a structural site represented by the followingstructural site A1:

—P—X—B—  [Chemical Formula 5] A1

wherein P is a structural unit of the phenolic hydroxyl group-containingaromatic hydrocarbon group (P), B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the methylene group (X) in a molecularstructure. Further specific examples thereof include structuresrepresented by the following structural formulas A2 and A3,

P—X—B—X—P  [Chemical Formula 6] A2

B—X—P—X—P—X—B  A3;

structures having, at the molecular end of a novolak structureincluding, as a repeating unit, a structure represented by the followingstructural formula A4 or A5:

a structure represented by the following structural formula A6:

B—X—  [Chemical Formula 8] A6;

or alternating copolymer structures including, as a repeating unit,structures represented by the following structural formulas A7 to A10:

In the present invention, the phenol resin can have various structures,as described above, and the dielectric dissipation factor of the epoxyresin cured article can be remarkably decreased by having a structurerepresented by the above structural formula A6 at the molecular end.Therefore, a phenol resin having a structure of the structural formulaA3, or a phenol resin including a repeating unit of the formula A4 or A7and a structure represented by the structural formula A6 at themolecular end is preferable. A phenol resin having a structure of thestructural formula A3 or a phenol resin including a repeating unit ofthe formula A4 and a structure represented by the structural formula A6at the molecular end is particularly preferable because the effect ofthe present invention is remarkably excellent.

As described hereinafter, the phenol resin can be obtained by reacting ahydroxy group-containing aromatic compound (a1), an alkoxygroup-containing aromatic compound (a2) and a carbonyl group-containingcompound (a3) and, in addition to the above compounds of variousstructures, a compound represented by the following structural formula:

P—X—B  [Chemical Formula 10]

wherein P is a structural unit of a phenolic hydroxyl group-containingaromatic hydrocarbon group (P), B is a structural unit of an alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of a methylene group (X) is simultaneouslyproduced and is contained in the phenol resin. In the present invention,it is preferred that the content of the compound is comparatively high,because melt viscosity of the phenol resin itself can be decreased andthe resulting epoxy resin cured article is excellent in dielectriccharacteristics. Specifically, the content of the component ispreferably within a range from 1 to 30% by mass based on the phenolresin. The content of the compound is preferably within a range from 3to 25% by mass, and particularly preferably from 3 to 15% by mass,because such an effect is remarkably exerted.

Similarly, as a result of the reaction of the hydroxy group-containingaromatic compound (a1), the alkoxy group-containing condensed polycyclicaromatic compound (a2) and the carbonyl group-containing compound (a3),the phenol resin as the product sometimes contain a compound having astructure represented by the following structural formula

B—X—B  [Chemical Formula 10]

wherein B is a structural unit of an alkoxy group-containing condensedpolycyclic aromatic hydrocarbon group (B) and X is a structural unit ofa methylene group (X). In the present invention, in view of heatresistance of the epoxy resin cured article, the content of the compoundis preferably as small as possible, and it is more preferable that thephenol resin does not contain any compound. Therefore, the content ofthe compound in the phenol resin is preferably 5% by mass or less, morepreferably 3% by mass or less, and particularly preferably 2% by mass orless.

The phenol resin preferably has a melt viscosity at 150° C., as measuredby an ICI viscometer, within a range from 0.1 to 5.0 dPa·s becausefluidity during molding and heat resistance of the cured article areexcellent. Furthermore, the phenol resin more preferably has a hydroxylgroup equivalent within a range from 120 to 500 g/eq. because flameretardancy and dielectric characteristics of the cured article are moreimproved. In the present invention, those having the hydroxyl groupequivalent and melt viscosity within such a range are employed as thenovel phenol resin of the present invention. When the hydroxyl groupequivalent is within a range from 200 to 350 g/eq., balance betweendielectric characteristics of the cured article and curability of thecomposition is particularly excellent.

In the phenol resin, a molar ratio of the phenolic hydroxylgroup-containing aromatic hydrocarbon group (P) to the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B),the former/the latter, is preferably within a range from 30/70 to 98/2because flame retardancy and dielectric characteristics of the curedarticle are more improved.

The phenol resin can be produced by the method described below indetail. The method for producing a phenol resin will be described indetail.

The phenol resin can be produced by reacting a hydroxy group-containingaromatic compound (a1), an alkoxy group-containing aromatic compound(a2) and a carbonyl group-containing compound (a3).

It is worthy of special mention that the reaction proceeds withoutcausing any hydrolysis, although the alkoxy group-containing aromaticcompound (a2) is used as a raw material. An alkoxy group obtained byalkoxylating a phenolic hydroxyl group is widely used in a technique ofprotecting a phenolic hydroxyl group and is easily hydrolyzed in astrong acidic environment, while an alkoxy group can be introduced intoa phenol resin structure without causing any hydrolysis in the presentinvention.

Specific examples of the hydroxy group-containing aromatic compound (a1)used in the above method for producing include unsubstituted phenolssuch as phenol, resorcinol and hydroquinone; monosubstituted phenolssuch as cresol, phenylphenol, ethylphenol, n-propylphenol,iso-propylphenol and t-butylphenol; disubstituted phenols such asxylenol, methylpropylphenol, methylbutylphenol, methylhexylphenol,dipropylphenol and dibutylphenol; trisubstituted phenols such asmesitol, 2,3,5-trimethylphenol and 2,3,6-trimethylphenol; and naphtholssuch as 1-naphthol, 2-naphthol and methylnaphthol.

These compounds may be used in combination.

Among these compounds, as described above, 1-naphthol, 2-naphthol,cresol and phenol are particularly preferable in view of dielectriccharacteristics and flame retardancy of the cured article.

Specific examples of the alkoxy group-containing aromatic compound (a2)include 1-methoxynaphthalene, 2-methoxynaphthalene,1-methyl-2-methoxynaphthalene, 1-methoxy-2-methylnaphthalene,1,3,5-trimethyl-2-methoxynaphthalene, 2,6-dimethoxynaphthalene,2,7-dimethoxynaphthalene, 1-ethoxynaphthalene, 1,4-dimethoxynaphthalene,1-t-butoxynaphthalene and 1-methoxyanthracene.

Among these compounds, 2-methoxynaphthalene and 2,7-dimethoxynaphthaleneare particularly preferable because an alkoxynaphthalene skeleton iseasily formed at the molecular end, and 2-methoxynaphthalene isparticularly preferable in view of dielectric characteristics.

Specific examples of the carbonyl group-containing compound (a3) includealiphatic aldehydes such as formaldehyde, acetaldehyde andpropionaldehyde; dialdehydes such as glyoxal; aromatic aldehydes such asbenzaldehyde, 4-methylbenzaldehyde, 3,4-dimethylbenzaldehyde,4-biphenylaldehyde and naphthylaldehyde; and ketone compounds such asbenzophenone, fluorenone and indanone.

Among these compounds, formaldehyde, benzaldehyde, 4-biphenylaldehydeand naphthylaldehyde are preferable because the resulting cured articleis excellent in flame retardancy, and formaldehyde is particularlypreferable because of excellent dielectric characteristics.

Examples of the method of reacting the hydroxy group-containing aromaticcompound (a1), the alkoxy group-containing condensed polycyclic aromaticcompound (a2) and the carbonyl group-containing compound (a3) include:

1) a method of charging a hydroxy group-containing aromatic compound(a1), an alkoxy group-containing condensed polycyclic aromatic compound(a2) and a carbonyl group-containing compound (a3), substantiallysimultaneously, and reacting them while stirring with heating in thepresence of a proper polymerization catalyst,2) a method of reacting 1 mol of an alkoxy group-containing condensedpolycyclic aromatic compound (a2) with 0.05 to 30 mols, preferably 2 to30 mols of a carbonyl group-containing compound (a3), charging a hydroxygroup-containing aromatic compound (a1) and reacting with the reactionproduct, and3) a method of previously mixing a hydroxy group-containing aromaticcompound (a1) with an alkoxy group-containing condensed polycyclicaromatic compound (a2), continuously or intermittently adding a carbonylgroup-containing compound (a3) in the system, and reacting with thereaction product. As used herein, substantially simultaneously meansthat all materials are charged until the reaction is accelerated byheating.

Among these methods, the methods 1) and 3) are preferable because it ispossible to control the content of a compound having a structurerepresented by the following structural formula:

P—X—B  [Chemical Formula 12]

and to satisfactorily suppress the production of a compound having astructure represented by the following structural formula:

B—X—B  [Chemical Formula 13]

The polymerization catalyst used herein is not specifically limited andan acid catalyst is preferable, and examples thereof include inorganicacids such as hydrochloric acid, sulfuric acid and phosphoric acid;organic acids such as methanesulfonic acid, p-toluenesulfonic acid andoxalic acid; and Lewis acids such as boron trifluoride, anhydrousaluminum chloride and zinc chloride. The content of the polymerizationcatalyst is preferably within a range from 0.1 to 5% by mass based onthe total mass of the materials to be charged.

A ratio of the hydroxy group-containing aromatic compound (a1), thealkoxy group-containing condensed polycyclic aromatic compound (a2) andthe carbonyl group-containing compound (a3) to be charged in thereaction is not specifically limited. A molar ratio of the hydroxygroup-containing aromatic compound (a1) to the alkoxy group-containingaromatic compound (a2), (a1)/(a2), is preferably within a range from30/70 to 98/2 and a ratio of the total number of mols of the hydroxygroup-containing aromatic compound (a1) and the alkoxy group-containingcondensed polycyclic aromatic compound (a2) to the number of mols of thecarbonyl group-containing compound (a3), {(a1)+(a2)}/(a3), is preferablywithin a range from 51/49 to 97/3.

To control the content of the compound having a structure represented bythe following structural formula:

P—X—B  [Chemical Formula 14]

and the content of the compound having a structure represented by thefollowing structural formula:

B—X—B  [Chemical Formula 15]

in the phenol resin produced by the method 1) or 3), the molar ratio(a1)/(a2) is preferably 2 or more and the ratio {(a1)+(a2)}/(a3) ispreferably within a range from 51/49 to 97/3.

When this reaction is conducted, an organic solvent can be used, ifnecessary. Examples of the usable organic solvent include, but are notlimited to, methyl cellosolve, ethyl cellosolve, toluene, xylene andmethyl isobutyl ketone. The content of the organic solvent is usuallywithin a range from 10 to 500% by mass, and preferably from 30 to 250%by mass, based on the total mass of the materials to be charged. Thereaction temperature is preferably within a range from 40 to 250° C.,and more preferably from 100 to 200° C. The reaction time is usuallywithin a range from 1 to 10 hours.

When the resulting polyvalent hydroxy compound shows high degree ofcoloration, antioxidants and reducing agents may be added so as tosuppress coloration. Examples of the antioxidant include, but are notlimited to, hindered phenolic compounds such as 2,6-dialkylphenolderivative; divalent sulfur-based compounds; and phosphite ester-basedcompounds containing a trivalent phosphorus atom. Examples of thereducing agent include, but are not limited to, hypophosphorous acid,phosphorous acid, thiosulfuric acid, sulfurous acid, hydrosulfite, orsalts thereof and zinc.

After the completion of the reaction, the reaction mixture is subjectedto neutralization or washing treatment until the pH value of thereaction mixture becomes the value within a range from 3 to 7, andpreferably from 4 to 7. The neutralization or washing treatment may beconducted by a conventional method. For example, when an acid catalystis used, basic substances such as sodium hydroxide, potassium hydroxide,sodium carbonate, ammonia, triethylenetetramine and aniline can be usedas a neutralizer. In case of neutralization, buffers such as phosphoricacid may be previously mixed. Alternatively, the pH value may beadjusted to the value within a range from 3 to 7 with oxalic acid or thelike after the pH is adjusted to the basic side. After subjecting to theneutralization or washing treatment, the unreacted material containingmainly the hydroxy group-containing aromatic compound (a1) and thealkoxy group-containing aromatic compound (a2), the organic solvent andby-product are distilled off while heating under reduced pressure andthen the product is concentrated, and thus the objective polyvalenthydroxy compound can be obtained. The unreacted material thus recoveredcan be reused. After the completion of the reaction, when a precisefiltration step is introduced into the treating operation, inorganicsalts and foreign matters can be removed by purification, and thereforethis method is preferable.

In epoxy resin composition (I) of the present invention, the phenolresin may be used alone, or used in combination with the other curingagent as far as the effects of the present invention are not adverselyaffected. Specifically, the other curing agent can be used incombination so that the content of the phenol resin is 30% by mass ormore, and preferably 40% by mass or more, based on the total mass of thecuring agent.

Examples of the other curing agent which can used in combination withthe phenol resin of the present invention include, but are not limitedto, amine-based compounds, amide-based compounds, acid anhydride-basedcompounds, phenolic compounds other than the above phenol resins, andpolyvalent phenol compounds of aminotriazine-modified phenol resins(polyvalent phenol compounds in which phenol nuclei are connected withmelamine or benzoguanamine).

Among these, phenol novolak resin, cresol novolak resin, aromatichydrocarbon formaldehyde resin-modified phenol resin, phenol aralkylresin, naphthol alaralkyl resin, naphthol novolak resin, naphthol-phenolco-condensed novolak resin, naphthol-cresol co-condensed novolak resin,biphenyl-modified phenol resin, biphenyl-modified naphthol resin andaminotriazine-modified phenol resin are preferable because of excellentflame retardancy, and compounds, for example, phenol resins having higharomatic properties and high hydroxyl group equivalent such as phenolaralkyl resin, naphthol aralkyl resin, biphenyl-modified phenol resinand biphenyl-modified naphthol resin, and aminotriazine-modified phenolresins having a nitrogen atom are used particularly preferably becausethe resulting cured article is excellent in flame retardancy anddielectric characteristics.

Examples of the epoxy resin (B) used in epoxy resin composition (I) ofthe present invention include bisphenol A type epoxy resin, bisphenol Ftype epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl typeepoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxyresin, bisphenol A novolak type epoxy resin, triphenylmethane type epoxyresin, tetraphenylethane type epoxy resin, dicyclopentadiene-phenoladdition reaction type epoxy resin, phenol aralkyl type epoxy resin,naphthol novolak type epoxy resin, naphtholaralkyl type epoxy resin,naphthol-phenol co-condensed novolak type epoxy resin, naphthol-cresolco-condensed novolak type epoxy resin, aromatic hydrocarbon formaldehyderesin-modified phenol resin type epoxy resin and biphenyl novolak typeepoxy resin. These epoxy resins may be used alone or in combination.

Among these epoxy resins, biphenyl type epoxy resin, naphthalene typeepoxy resin, phenol aralkyl type epoxy resin, biphenyl novolak typeepoxy resin and xanthene type epoxy resin are particularly preferablebecause of excellent flame retardancy and dielectric characteristics.

The contents of the epoxy resin (B) and the curing agent in epoxy resincomposition (I) of the present invention are not specifically limited.The content of an active group in the curing agent containing the phenolresin (A) is preferably within a range from 0.7 to 1.5 equivalents basedon 1 equivalent of the total of epoxy groups of the epoxy resin (B)because the resulting cured article is excellent in characteristics.

If necessary, curing accelerators can also be added to epoxy resincomposition (I) of the present invention. Various curing acceleratorscan be used and examples thereof include phosphorous-based compound,tertiaryamine, imidazole, organic acid metal salt, Lewis acid and aminecomplex salt. When used as semiconductor encapsulation materials,triphenylphosphine is preferable in case of a phosphorous-based compoundand 1,8-diazabicyclo-[5.4.0]-undecene (DBU) is preferable in case of atertiary amine because of excellent curability, heat resistance,electrical characteristics and moisture resistant reliability.

Another epoxy resin composition (II) of the present invention is anepoxy resin composition including an epoxy resin and a curing agent asessential components, wherein the epoxy resin has the respectivestructural units of:

a glycidyloxy group-containing aromatic hydrocarbon group (E),

an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and

a divalent hydrocarbon group (X) selected from methylene, an alkylidenegroup and an aromatic hydrocarbon structure-containing methylene group,and also has, in a molecular structure, a structure in which theglycidyloxy group-containing aromatic hydrocarbon group (E) and thealkoxy group-containing condensed polycyclic aromatic hydrocarbon group(B) are bonded via the divalent hydrocarbon group (X) selected frommethylene, the alkylidene group and the aromatic hydrocarbonstructure-containing methylene group.

That is, the epoxy resin in epoxy resin composition (II) is obtained byreacting a phenol resin constituting epoxy resin composition (I) withepihalohydrin, thereby epoxidating the phenol resin, and has a basicskeleton common to the phenol resin. Therefore, similar to the case ofthe phenol resin, the aromatic content in the molecular structureincreases and excellent heat resistance is imparted to the cured articleand also the concentration of the epoxy group can be appropriatelydecreased and the alkoxy group is contained in the molecular structure,and thus the dielectric constant and dielectric dissipation factor ofthe cured article can be decreased.

Similar to the phenol resin, the epoxy resin essentially contains, in amolecular structure, a structural site represented by the followingstructural site Y1:

-E-X—B—  [Chemical Formula 16] Y1

wherein E is a structural unit of the glycidyloxy group-containingaromatic hydrocarbon group (E), B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the methylene group (X).

In the present invention, because of a characteristic chemicalstructure, an aromatic content in the molecular structure increases andexcellent heat resistance is exhibited. Since a crosslink point in acured article exists in the vicinity of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group (B), it is possible toreduce an adverse influence such as decrease in the dielectric constantand dielectric dissipation factor caused by a secondary hydroxyl groupproduced during curing, and thus excellent dielectric characteristicscan be exhibited. It is worthy of special mention to exhibit excellentdielectric characteristics while introducing a functional group havingcomparatively high polarity such as alkoxy group.

The glycidyloxy group-containing aromatic hydrocarbon group (E) is notspecifically limited and preferred examples thereof include aromatichydrocarbon groups represented by the following structural formulas E1to E16 because of excellent dielectric performances.

When each structure is located at the molecular end, a monovalentaromatic hydrocarbon group is formed. Among the structures describedabove, the bonding site of those having at least two bonding sites withthe other structural site on the naphthalene skeleton may exist on thesame or different nucleus.

Among the glycidyloxy group-containing aromatic hydrocarbon groups (E)described above in detail, those having a methyl group as a substituenton the aromatic ring can impart excellent flame retardancy to an epoxyresin cured article itself and it becomes possible to design ahalogen-free material which has highly been required in the field ofelectronic components, recently.

Furthermore, the glycidyloxy group-containing aromatic hydrocarbongroups (E) having a methyl group at the ortho-position of the phenolskeleton typified by those represented by the structural formulas E6,E7, ES and E9 are preferable because a remarkable effect of improvingheat resistance and dielectric characteristics of the cured article isexerted.

The alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B) contained in the epoxy resin structure is specifically thesame as that in the phenol resin of the above epoxy resin composition(I).

The methylene group (X) contained in the epoxy resin structure isspecifically the same as that in the phenol resin of the above epoxyresin composition (I).

The epoxy resin used in the present invention can employ any combinationof the structures shown in the respective specific examples of thestructural sites (E), (B) and (X). As described above, the molecularstructure of the phenol resin composed of each structural site hasessentially a structural site represented by the following structuralsite Y1:

-E-X—B  [Chemical Formula 18] Y1

wherein E is a structural unit of the glycidyloxy group-containingaromatic hydrocarbon group (E), B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the methylene group (X) in a molecularstructure. Specific examples thereof include structures represented bythe following structural formulas Y2 and Y3,

E-X—B—X-E  [Chemical Formula 19] Y2;

B—X-E-X-E-X—B  Y3

structures having, at the molecular end of a novolak structureincluding, as a repeating unit, a structure represented by the followingstructural formula Y4 or Y5:

a structure represented by the following structural formula A6:

B—X—  [Chemical Formula 21] A6;

and alternating copolymer structure including, as a repeating unit,structures represented by the following structural formulas Y7 to Y10:

In the present invention, the epoxy resin can have various structures,as described above, and the dielectric dissipation factor of the epoxyresin cured article can be remarkably decreased by having a structurerepresented by the above structural formula A6 at the molecular end.Therefore, an epoxy resin having a structure of the structural formulaY3, or a phenol resin including a repeating unit of the formula Y4 or Y7and a structure represented by the structural formula A6 at themolecular end is preferable. An epoxy resin having a structure of thestructural formula Y3 or an epoxy resin including a repeating unit ofthe formula Y4 and a structure represented by the structural formula A6at the molecular end is particularly preferable because the effect ofthe present invention is remarkably excellent.

As described hereinafter, the epoxy resin can be produced by reacting ahydroxy group-containing aromatic compound (a1), an alkoxygroup-containing aromatic compound (a2) and a carbonyl group-containingcompound (a3) and reacting the reaction product with epihalohydrin. Inthis case, since compounds of various structures are produced in theproduction of the phenol resin as a precursor of the epoxy resin,finally obtained epoxy resin contain compounds of various structures. Inthe present invention, a compound represented by the followingstructural formula:

E-X—B  [Chemical Formula 23]

wherein E is a structural unit of a glycidyloxy group-containingaromatic hydrocarbon group (E), B is a structural unit of an alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of a methylene group (X) is simultaneouslyproduced and is contained in the epoxy resin.

Similar to the above phenol resin, it is preferred that the content ofthe compound is comparatively high in view of melt viscosity anddielectric characteristics. The content of the compound is preferablywithin a range from 1 to 30% by mass, more preferably from 3 to 25% bymass, and particularly preferably from 3 to 15% by mass, based on theresin.

Similarly, since the epoxy resin is produced by reacting the hydroxygroup-containing aromatic compound (a1), the alkoxy group-containingcondensed polycyclic aromatic compound (a2) and the carbonylgroup-containing compound (a3), the epoxy resin as the product sometimescontain a compound having a structure represented by the followingstructural formula:

B—X—  [Chemical Formula 24]

wherein B is a structural unit of an alkoxy group-containing condensedpolycyclic aromatic hydrocarbon group (B) and X is a structural unit ofa methylene group (X) In view of heat resistance of the epoxy resincured article, the content of the compound is preferably as small aspossible and it is more preferable that the epoxy resin does not containany compound. Therefore, the content of the compound in the epoxy resinis preferably 5% by mass or less, more preferably 3% by mass or less,and particularly preferably 2% by mass or less.

The epoxy resin preferably has an epoxy group equivalent within a rangefrom 200 to 500 g/eq. because flame retardancy and dielectriccharacteristics of the cured article are more improved. Furthermore, theepoxy resin preferably has a melt viscosity at 150° C., as measured byan ICI viscometer, within a range from 0.1 to 5.0 dPa·s because fluidityduring molding and heat resistance of the cured article are excellent.In the present invention, those having the epoxy group equivalent andmelt viscosity within such a range are employed as a novel epoxy resinof the present invention. When the epoxy group equivalent is within arange from 260 to 420 g/eq., balance between dielectric characteristicsof the cured article and curability of the composition is particularlyexcellent.

In the epoxy resin, a ratio of the glycidyloxy group-containing aromatichydrocarbon group (E) to the alkoxy group-containing condensedpolycyclic aromatic hydrocarbon group (B), the former/the latter, ispreferably within a range from 30/70 to 98/2 because flame retardancyand dielectric characteristics of the cured article are more improved.

The epoxy resin can be produced by the method described below in detail.

Specifically, the objective epoxy resin can be produced by producing aphenol resin in epoxy resin composition (I) by the above method andreacting the phenol resin with epihalohydrin. For example, there can beemployed a method of adding 2 to 10 mols of epihalohydrin to 1 mol of aphenolic hydroxyl group in the phenol resin and reacting at atemperature of 20 to 120° C. for 0.5 to 10 hours while simultaneously orgradually adding 0.9 to 2.0 mols of a basic catalyst to 1 mol of aphenolic hydroxyl group. This basic catalyst may be used in the form ofa solid or an aqueous solution. When using the aqueous solution, therecan be used a method of continuously adding the aqueous solution,continuously distilling off water and epihalohydrins from the reactionmixture under reduced pressure or normal pressure, separating them,removing water and continuously returning epihalohydrins into thereaction mixture.

In case of industrial production, entire epihalohydrins used in aninitial batch for production of the epoxy resin are new epihalohydrins.However, it is preferred to use epihalohydrin recovered from the crudereaction product in combination with new epihalohydrins correspondingthe epihalohydrins consumed during the reaction in the followingbatches. At this time, the epihalohydrin to be used is not specificallylimited and examples thereof include epichlorohydrin, epibromohydrin andβ-methylepichlorohydrin. Among these epihalohydrins, epichlorohydrin ispreferable because it is available with ease.

Specific examples of the basic catalyst include alkali earth metalhydroxide, alkali metal carbonic acid salt and alkali metal hydroxide.In view of excellent catalytic activity of the reaction for synthesis ofan epoxy resin, alkali metal hydroxide is preferable and examplesthereof include sodium hydroxide and potassium hydroxide. These basiccatalysts may be used in the form of an aqueous solution having aconcentration of about 10 to 55% by mass or a solid. The reaction ratein the synthesis of an epoxy resin can be increased by using incombination with an organic solvent. Examples of the organic solventinclude, but are not limited to, ketones such as acetone and methylethyl ketone; alcohols such as methanol, ethanol, 1-propyl alcohol,isopropyl alcohol, 1-butanol, secondary butanol and tertiary butanol;cellosolves such as methyl cellosolve and ethyl cellosolve; ethers suchas tetrahydrofuran, 1,4-dioxane, 1,3-dioxane and diethoxyethane; andaprotic polar solvents such as acetonitrile, dimethyl sulfoxide anddimethyl formamide. These organic solvent may be used alone, or may beused in combination so as to adjust polarity.

The reaction product of the above epoxydation reaction is washed withwater and then the unreacted epihalohydrin and the organic solvent usedin combination are distilled off by distillation with heating underreduced pressure. To obtain an epoxy resin containing a small amount ofa hydrolyzable halogen, the resulting epoxy resin is dissolved in anorganic solvent such as toluene, methyl isobutyl ketone or methyl ethylketone and an aqueous solution of an alkali metal hydroxide such assodium hydroxide or potassium hydroxide is added and then the reactioncan be further conducted. For the purpose of improving the reactionrate, the reaction can be conducted in the presence of a phase transfercatalyst such as quaternary ammonium salt or crown ether. In case ofusing the phase transfer catalyst, the amount is preferably within arange from 0.1 to 3.0% by mass based on the amount of the epoxy resin tobe used. After the completion of the reaction, the resulting salt isremoved by filtration or washing with water, and then the solvent suchas toluene or methyl isobutyl ketone is distilled off with heating underreduce pressure to obtain a high-purity epoxy resin.

In epoxy resin composition of the present invention (II), the epoxyresin (A) obtained by the method of the present invention can be usedalone or in combination with the other epoxy resin as far as the effectsof the present invention are not adversely affected. When using incombination, the content of the epoxy resin of the present invention ispreferably 30% by mass or more, and particularly preferably 40% by massor more, based on the entire epoxy resin.

As the epoxy resin, which can be used in combination with the epoxyresin of the present invention, various epoxy resins can be used.Examples thereof include bisphenol A type epoxy resin, bisphenol F typeepoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxyresin, phenol novolak type epoxy resin, cresol novolak type epoxy resin,bisphenol A novolak type epoxy resin, triphenylmethane type epoxy resin,tetraphenylethane type epoxy resin, dicyclopentadiene-phenol additionreaction type epoxy resin, phenol aralkyl type epoxy resin, naphtholnovolak type epoxy resin, naphthol aralkyl type epoxy resin,naphthol-phenol co-condensed novolak type epoxy resin, naphthol-cresolco-condensed novolak type epoxy resin, aromatic hydrocarbon formaldehyderesin-modified phenol resin type epoxy resin and biphenyl novolak typeepoxy resin. Among these epoxy resins, a phenol aralkyl type epoxyresin, a biphenyl novolak type epoxy resin, a naphthol novolak typeepoxy resin containing a naphthalene skeleton, a naphthol aralkyl typeepoxy resin, a naphthol-phenol co-condensed novolak type epoxy resin, anaphthol-cresol co-condensed novolak type epoxy resin, a crystallinebiphenyl type epoxy resin, a tetramethyl biphenyl type epoxy resin, anda xanthene type epoxy resin represented by the following structuralformula:

are particularly preferable because a cured article having excellentflame retardancy and dielectric characteristics can be obtained.

As the curing agent used in epoxy resin composition of the presentinvention (II), known various curing agents for epoxy resin such asamine-based compounds, amide-based compounds, acid anhydride-basedcompounds and phenolic compounds can be used. Specific examples of theamine-based compound include diaminodiphenylmethane, diethylenetriamine,triethylenetetramine, diaminodiphenylsulfon, isophoronediamine,imidazol, BF₃-amine complex and guanidine derivative; specific examplesof the amide-based compound include dicyandiamide, and polyamide resinsynthesized from a dimer of linolenic acid and ethylenediamine; specificexamples of the acid anhydride-based compound include phthalicanhydride, trimellitic anhydride, pyromellitic anhydride, maleicanhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalicanhydride, methylnadic anhydride, hexahydrophthalic anhydride andmethylhexahydrophthalic anhydride; and specific examples of thephenol-based compound include polyvalent phenol compounds such as phenolnovolak resin, cresol novolak resin, aromatic hydrocarbon formaldehyderesin-modified phenol resin, dicyclopentadienephenol addition typeresin, phenol aralkyl resin (popular name, xylok resin), naphtholaralkyl resin, trimethylolmethane resin, tetraphenylolethane resin,naphthol novolak resin, naphthol-phenol co-condensed novolak resin,naphthol-cresol co-condensed novolak resin, biphenyl-modified phenolresin (polyvalent phenol compound in which a phenol nucleus is connectedthrough a bismethylene group), biphenyl-modified naphthol resin(polyvalent naphthol compound in which a phenol nucleus is connectedthrough a bismethylene group), aminotriazine-modified phenol resin(polyvalent phenol compound in which phenol nucleus is connected throughmelamine or benzoguanamine).

Among these compounds, those containing a lot of aromatic skeletons inthe molecular structure are preferable in view of the flame retardanteffect and, for example, a phenol novolak resin, a cresol novolak resin,an aromatic hydrocarbon formaldehyde resin-modified phenol resin, aphenol aralkyl resin, a naphthol aralkyl resin, a naphthol novolakresin, a naphthol-phenol co-condensed novolak resin, a naphthol-cresolco-condensed novolak resin, a biphenyl-modified phenol resin, abiphenyl-modified naphthol resin and an aminotriazine-modified phenolresin are preferable because of excellent flame retardancy.

In the present invention, the above phenol resin used as an essentialcomponent in epoxy resin composition (I) is preferable and a novelphenol resin of the present invention is particularly preferable becausea remarkable effect of decreasing the dielectric constant and dielectricdissipation factor is exerted. Furthermore, the phenol resin composed ofan alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B) represented by the structural formula (1′), a methylene group(X) represented by the structural formula (2′) and a phenolic hydroxylgroup-containing aromatic hydrocarbon group (P) represented by theformula (3) or (4) is particularly preferable because a remarkable flameretardant effect is exerted.

The contents of the epoxy resin and the curing agent in epoxy resincomposition of the present invention (II) are not specifically limited.The content of an active group in the curing agent is preferably withina range from 0.7 to 1.5 equivalents based on 1 equivalent of the totalof epoxy groups in the epoxy resin containing the epoxy resin becausethe resulting cured article is excellent in characteristics.

If necessary, curing accelerators can also be added to epoxy resincomposition of the present invention (II). Various curing acceleratorscan be used and examples thereof include phosphorous-based compound,tertiary amine, imidazole, organic acid metal salt, Lewis acid and aminecomplex salt. When used as semiconductor encapsulation materials,triphenylphosphine is preferable in case of a phosphorous-based compoundand 1,8-diazabicyclo-[5.4.0]-undecene (DBU) is preferable in case of atertiary amine because of excellent curability, heat resistance,electrical characteristics and moisture resistant reliability.

In the above-described epoxy resin compositions (I) and (II) of thepresent invention, since the resin itself has an excellent effect ofimparting flame retardancy according to selection of the molecularstructure of the epoxy resin or a curing agent thereof, the curedarticle is excellent in flame retardancy even if a conventionally useflame retardant is not mixed. However, in order to exhibit moreexcellent flame retardancy, in the field of the semiconductorencapsulation material, a non-halogen flame retardant (C) containingsubstantially no halogen atom may be mixed as far as moldability in theencapsulation step and reliability of the semiconductor device are notdeteriorated.

The epoxy resin composition containing such as non-halogen flameretardant (C) substantially contains no halogen atom, but may contain atrace amount (about 5000 ppm or less) of a halogen atom due toimpurities derived from epihalohydrin contained in the epoxy resin.

Examples of the non-halogen flame retardant (C) includephosphorous-based flame retardant, nitrogen-based flame retardant,silicone-based flame retardant, inorganic-based flame retardant andorganic metal salt-based flame retardant and these flame retardant arenot specifically limited when used and may be used alone, or a pluralityof the same flame retardants may be used or different flame retardantscan be used in combination.

AS the phosphorous-based flame retardant, inorganic and organic flameretardants can be used. Examples of the inorganic compound includeammonium phosphates such as red phosphorus, monoammonium phosphate,diammonium phosphate, triammonium phosphate and ammonium polyphosphate;and inorganic nitrogen-containing phosphorus compounds such asphosphoric acid amide.

For the purpose of preventing hydrolysis of red phosphorus, it ispreferably subjected to a surface treatment. Examples of the method of asurface treatment include (i) a method of coating with an inorganiccompound such as magnesium hydroxide, aluminum hydroxide, zinchydroxide, titanium hydroxide, bismuth oxide, bismuth hydroxide, bismuthnitrate or a mixture thereof, (ii) a method of coating with an inorganiccompound such as magnesium hydroxide, aluminum hydroxide, zinc hydroxideor titanium hydroxide, and a mixture of a thermosetting resin such asphenol resin, (iii) and a method of double-coating a coating film madeof an inorganic compound such as magnesium hydroxide, aluminumhydroxides zinc hydroxide or titanium hydroxide with a thermosettingresin such as phenol resin.

Examples of the organic phosphorous-based compound include commodityorganic phosphorous-based compounds such as phosphate ester compound,phosphonic acid compound, phosphinic acid compound, phosphine oxidecompound, phospholan compound and organic nitrogen-containing phosphoruscompound; cyclic organic phosphorus compounds such as9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide,10-(2,5-dihydrooxyphenyl)-10H-9-oxa-10-phsophaphenanthrene=10-oxide and10-(2,7-dihydrooxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene=10-oxide;and derivatives obtained by reacting the cyclic organic phosphoruscompound with a compound such as epoxy resin or phenol resin.

The amount is appropriately selected according to the kind of thephosphorous-based flame retardant, other components of the epoxy resincomposition and the degree of desired flame retardancy. When redphosphorus is used as the non-halogen flame retardant in 100 parts bymass of an epoxy resin composition containing an epoxy resin, a curingagent, a non-halogen flame retardant and other fillers and additives,the amount is preferably within a range from 0.1 to 2.0 parts by mass.When an organic phosphorous compound is used, the amount is preferablywithin a range from 0.1 to 10.0 parts by mass, and particularlypreferably from 0.5 to 6.0 parts by mass.

When the phosphorous-based flame retardant is used, thephosphorous-based flame retardant may be used in combination withhydrotalcite, magnesium hydroxide, boron compound, zirconium oxide,black dye, calcium carbonate, zeolite, zinc molybdate and activatedcarbon.

Examples of the nitrogen-based flame retardant include triazinecompound, cyanuric acid compound, isocyanuric acid compound andphenothiazine, and a triazine compound, a cyanuric acid compound and anisocyanuric acid compound are preferable.

Examples of the triazine compound include, in addition to melamine,acetoguanamine, benzoguanamine, melon, melam, succinoguanamine,ethylenedimelamine, melamine polyphosphate and triguanamine, (i)aminotriazine sulfate compound such as guanylmelamine sulfate, melemsulfate or melam sulfate, (ii) cocondensate of phenols such as phenol,cresol, xylenol, butylphenol and nonylphenol, melamines such asmelamine, benzoguanamin, acetoguanamine and formguanamine, andformaldehyde, (iii) mixture of the cocondensate (ii) and phenol resinssuch as phenolformaldehyde condensate, and (iv) those obtained bymodifying the cocondensate (ii) and the mixture (iii) with tung oil orisomerized linseed oil.

Specific examples of the cyanuric acid compound include cyanuric acidand melamine cyanurate.

The amount of the nitrogen-based flame retardant is appropriatelyselected according to the kind of the nitrogen-based flame retardant,other components of the epoxy resin composition and the degree ofdesired flame retardancy, and is preferably within a range from 0.05 to10 parts by mass, and particularly preferably from 0.1 to 5 parts bymass, based on 100 parts by mass of an epoxy resin compositioncontaining an epoxy resin, a curing agent, a non-halogen flame retardantand other fillers and additives.

When the nitrogen-based flame retardant is used, a metal hydroxide and amolybdenum compound may be used in combination.

The silicone-based flame retardant is not specifically limited as far asit is an organic compound having a silicon atom, and examples thereofinclude silicone oil, silicone rubber and silicone resin.

The amount of the silicone-based flame retardant is appropriatelyselected according to the kind of the silicone-based flame retardant,other components of the epoxy resin composition and the degree ofdesired flame retardancy, and is preferably within a range from 0.05 to20 parts by mass based on 100 parts by mass of an epoxy resincomposition containing an epoxy resin, a curing agent, a non-halogenflame retardant and other fillers and additives. When the silicone-basedflame retardant is used, a molybdenum compound and alumina may be usedin combination.

Examples of the inorganic-based flame retardant include metal hydroxide,metal oxide, metal carbonate compound, metal powder, boron compound andlow melting point glass.

Specific examples of the metal hydroxide include aluminum hydroxide,magnesium hydroxide, dolomite, hydrotalcite, calcium hydroxide, bariumhydroxide and zirconium hydroxide.

Specific examples of the metal oxide include zinc molybdate, molybdenumtrioxide, zinc stannate, tin oxide, aluminum oxide, iron oxide, titaniumoxide, manganese oxide, zirconium oxide, zinc oxide, molybdenum oxide,cobalt oxide, bismuth oxide, chromium oxide, nickel oxide, copper oxideand tungsten oxide.

Specific examples of the metal carbonate compound include zinccarbonate, magnesium carbonate, calcium carbonate, barium carbonate,basic magnesium carbonate, aluminum carbonate, iron carbonate, cobaltcarbonate and titanium carbonate.

Specific examples of the metal powder include aluminum, iron, titanium,manganese, zinc, molybdenum, cobalt, bismuth, chromium, nickel, copper,tungsten and tin powders.

Specific examples of the boron compound include zinc borate, zincmetaborate, barium metaborate, boric acid and borax.

Specific examples of the low melting point glass include Seaplea(Bokusui Brown Co Ltd.), hydrated glass SiO₂—MgO—H₂O, PbO—B₂O₃-based,ZnO—P₂O₅—MgO-based, P₂O₅—B₂O₃—PbO—MgO-based, P—Sn—O—F-based,PbO—V₂O₅—TeO₂-based, Al₂O₃—H₂O-based and lead borosilicate-based glassycompounds.

The amount of the inorganic-based flame retardant is appropriatelyselected according to the kind of the inorganic-based flame retardant,other components of the epoxy resin composition and the degree ofdesired flame retardancy, and is preferably within a range from 0.05 to20 parts by mass, and particularly preferably from 0.5 to 15 parts bymass, based on 100 parts by mass of an epoxy resin compositioncontaining an epoxy resin, a curing agent, a non-halogen flame retardantand other fillers and additives.

Examples of the organic metal salt-based flame retardant includeferrocene, acetylacetonate metal complex, organic metal carbonylcompound, organic cobalt salt compound, organic sulfonic acid metalsalt, and compound obtained by ionic bonding or coordinate bonding of ametal atom and an aromatic compound or a heterocyclic compound.

The amount of the organic metal salt-based flame retardant isappropriately selected according to the kind of the organic metalsalt-based flame retardant, other components of the epoxy resincomposition and the degree of desired flame retardancy, and ispreferably within a range from 0.005 to 10 parts by mass based on 100parts by mass of an epoxy resin composition containing an epoxy resin, acuring agent, a non-halogen flame retardant and other fillers andadditives.

If necessary, the epoxy resin composition of the present invention cancontain inorganic fillers. Examples of the inorganic filler includefused silica, crystalline silica, alumina, silicon nitride and aluminumhydroxide. When the amount of the inorganic filler is particularlylarge, fused silica is preferably used. The fused silica can be used ina crushed or spherical form, and the spherical form is preferably usedso as to increase the amount of the fused silica and to suppress anincrease in melt viscosity of a molding material. To further increasethe amount of the spherical silica, it is preferred to appropriatelyadjust particle size distribution of the spherical silica. Takingaccount of flame retardancy, the content of the filler is preferablyhigh and is particularly preferably 65% by mass or more based on thetotal amount of the epoxy resin composition. When used in the conductivepaste, a conductive filler such as silver powder or copper powder can beused.

To epoxy resin composition (I) or (II) of the present invention, variousadditives such as silane coupling agent, releasant, pigment andemulsifier can be added, if necessary.

Epoxy resin composition (I) or (II) of the present invention can beobtained by uniformly mixing the above-described components. The epoxyresin composition of the present invention, which contains an epoxyresin of the present invention, a curing agent and, if necessary, acuring accelerator, can be easily formed into a cured article by way ofthe common methods. Examples of the cured article include molded curedarticles such as laminate, cast article, adhesive layer, coating filmand film.

Examples of uses of the epoxy resin composition of the present inventioninclude semiconductor encapsulation materials, resin compositions usedfor laminates and electronic circuit boards, resin casting materials,adhesives, interlayer insulation materials for buildup substrates, andcoating materials such as insulating paint. The epoxy resin compositionof the present invention can be preferably used as semiconductorencapsulation materials.

The epoxy resin composition for semiconductor encapsulation material isobtained by the following procedure. That is, an epoxy resin andcompounding agents such as curing agent and filler are sufficientlymixed using an extruder, a kneader or a roll to obtain a uniformmelt-mixing type epoxy resin composition. In that case, silica isusually used as the filler and the amount of the filler is preferablywithin a range from 30 to 95 parts by mass based on 100 parts by mass ofthe epoxy resin composition. To improve flame retardancy, moistureresistance and solder cracking resistance and to decrease the linearexpansion coefficient, the amount of the filler is particularlypreferably 70 parts by mass or more. To noticeably enhance the effect,the amount of the filler is adjusted to 80 parts by mass or more. Incase of semiconductor package molding, the composition is molded bycasting or using a transfer molding machine or an injection moldingmachine and then heated at 50 to 200° C. for 2 to 10 hours to obtain asemiconductor device as a molded article.

The epoxy resin composition of the present invention can be formed intoa composition for printed circuit board, for example, a resincomposition for prepreg. According to the viscosity, the epoxy resincomposition can be used without using a solvent, and the resincomposition for prepreg is preferably prepared by forming into a varnishusing an organic solvent. As the organic solvent, a polar solvent havinga boiling point of 160° C. or lower such as methyl ethyl ketone, acetoneor dimethyl formamide is preferably used, and these organic solvents canbe used alone or in combination. A prepreg as a cured article can beobtained by impregnating various reinforcing base materials such aspaper, glass cloth, glass nonwoven fabric, aramid paper, aramid cloth,glass mat and glass roving cloth with the resulting varnish and byheating at a temperature corresponding to the kind of the solvent,preferably 50 to 170° C. The contents of the resin composition and thereinforcing base material are not specifically limited, and the contentof the resin in the prepreg is preferably adjusted within a range from20 to 60% by mass. When a copper-cladded laminate is produced using theepoxy resin composition, the copper-cladded laminate can be obtained bylaying the resulting prepregs one upon another using a conventionalmethod and appropriately laying a copper foil thereon, followed bypress-contacting with heating at 170 to 250° C. under pressure of 1 to10 MPa for 10 minutes to 3 hours.

When the epoxy resin composition of the present invention is used as aresist ink, for example, a cationic polymerization catalyst is used as acuring agent of epoxy resin composition (II) and a pigment, talc and afiller are added to give a composition for resist ink, and then thecomposition is coated onto a printed board using a screen printingmethod to give a resist ink cured article.

When the epoxy resin composition of the present invention is used as aconductive paste, for example, a method wherein conductive fineparticles are dispersed in the epoxy resin composition to give acomposition for anisotropic conductive layer; or a method wherein thecomposition is prepared into a paste resin composition for connection ofcircuits, which is liquid at room temperature, or an anisotropicconductive adhesive can be adopted.

An interlayer insulation material for buildup substrate can be obtainedfrom the epoxy resin composition of the present invention in thefollowing manner. That is, the curable resin composition obtained byappropriately mixing a rubber, a filler or the like is coated onto awiring board having an inner layer circuit formed thereon using a spraycoating method or a curtain coating method, and then cured. Ifnecessary, predetermined holes such as throughholes are formed and thewiring board is treated with a roughening agent. The surface is washedwith hot water to form irregularity and the wiring board is plated withmetal such as copper. The plating method is preferably electrolessplating or electroplating treatment, and examples of the rougheningagent include oxidizing agent, alkali and organic solvent. Such anoperation is optionally repeated successively, and a buildup substratecan be formed by way of alternating layers of a resin insulating layerand a conductive layer having a predetermined circuit pattern.Throughholes are formed after forming the outermost resin insulatinglayer. It is also possible to produce a buildup substrate withoutconducting the step of forming a roughened surface and a plating step bycontact-bonding a copper foil coated with a semicured resin compositionon a wiring board having an inner layer circuit formed thereon withheating at 170 to 250° C.

The cured article of the present invention may be obtained by aconventional method of curing an epoxy resin composition. For example,heating temperature conditions may be appropriately selected by the kindof curing agents to be used in combination and purposes, and thecomposition obtained by the above method may be heated at a temperaturewithin a range from room temperature to about 250° C. The epoxy resincomposition may be molded by a conventional method and the conditionspeculiar to the epoxy resin composition of the present invention are notrequired.

Therefore, an environmentally friendly epoxy resin material capable ofexhibiting excellent flame retardancy can be obtained by using thephenol resin even if a halogen-based flame retardant is not used.Excellent dielectric characteristics can realize an increase inoperation speed of a high-frequency device and enable molecular designcorresponding to the level of the above-described objectiveperformances. The phenol resin can be produced by the method forproducing of the present invention easily and effectively.

EXAMPLES

The present invention will now be described in detail by way of examplesand comparative examples. In the following examples and comparativeexamples, parts and percentages are by mass unless otherwise specified.Melt viscosity at 150° C., GPC, NMR and MS spectrum were measured underthe following conditions.

1) Melt viscosity at 150° C.: in accordance with ASTM D42872) Method for measurement of softening point: JIS K7234

3) GPC:

Apparatus: HLC-8220 GPC manufactured by Tosoh Corporation

Column: TSK-GEL G2000HXL+G2000HXL+G300QHXL+G4000HXL manufactured byTosoh Corporation

Solvent: tetrahydrofuran

Flow rate: 1 ml/min

Detector: RI

4) NMR: NMR GSX270 manufactured by JEOL Ltd.5) MS: Double-focusing mass spectrometer AX505H (ED505H) manufactured byJEOL Ltd.

In the examples and comparative examples, “P—X—B”, “E-X—B” and “B—X—B”mean a structure of a compound including the following structural unitswherein P is a structural unit of a phenolic hydroxyl group-containingaromatic hydrocarbon group (P), E is a structural unit of a glycidyloxygroup-containing aromatic hydrocarbon group (E), B is an alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B),and X is a structural unit of a divalent hydrocarbon group (X) selectedfrom methylene, an alkylidene group and an aromatic hydrocarbonstructure-containing methylene group.

Example 1 Synthesis of Phenol Resin (A-1)

In a flask equipped with a thermometers a condenser tube, a distillingtube, a nitrogen introducing tube and a stirrer, 432.4 g (4.00 mols) ofo-cresol, 158.2 g (1.00 mols) of 2-methoxynaphthalene and 179.3 g (2.45mols) of 41% paraformaldehyde were charged, mixed with 9.0 g of oxalicacid and then reacted at 100° C. for 3 hours by heating to 100° C. Whilecollecting water using a distilling tube, 73.2 g (1.00 mols) of 41%paraform was added dropwise over one hour. After the completion ofdropwise addition, the reaction was conducted at 150° C. for 2 hours byheating to 150° C. over one hour. After the completion of the reaction,1500 g of methyl isobutyl ketone was further added and the reactionsolution was transferred to a separatory funnel, followed by washingwith water. After washing with water until rinse water shows neutrality,unreacted o-cresol, 2-methoxynaphthalene and methyl isobutyl ketone wereremoved from the organic layer with heating under reduced pressure toobtain 531 g of a phenol resin (A-1) having a structural unitrepresented by the following structural formula:

The resulting phenol resin had a softening point of 76° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 1.0 dPa·s and a hydroxyl group equivalent of164 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 1, a C¹³ NMRchart is shown in FIG. 2 and an MS spectrum is shown in FIG. 3. GPCanalysis revealed that the content of a compound having a structurerepresented by “P—X—B” was 11% by mass and the content of a compoundhaving a structure represented by “B—X—B” was 1% by mass. As a result ofthe measurement of the mass of the recovered unreacted o-cresol and2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 79/21. The remaining of methoxy group wasconfirmed from a signal of a methoxy group observed at 55 ppm in NMR andit is confirmed from a hydroxyl group equivalent that the methoxy groupin the compound is not decomposed. Also it could be confirmed that theresulting resin has a structure represented by “B—X—” at the molecularend.

Example 2 Synthesis of Phenol Resin (A-2)

In a flask equipped with a thermometer, a condenser tube, a distillingtube, and a stirrer, 169.4 g (1.80 mols) of phenol, 31.6 g (0.20 mols)of 2-methoxynaphthalene and 32.6 g (1.00 mols) of 92% paraformaldehydewere charged, mixed with 5.0 g of oxalic acid, reacted at 100° C. forone hour by heating to 100° C. over one hour, and then reacted at 140°C. for one hour. After the completion of the reaction, 700 g of methylisobutyl ketone was further added and the reaction solution wastransferred to a separatory funnel, followed by washing with water.After washing with water until rinse water shows neutrality, unreactedphenol, 2-methoxynaphthalene and methyl isobutyl ketone were removedfrom the organic layer with heating under reduced pressure to obtain 149g of a phenol resin (A-2) having a structural unit represented by thefollowing structural formula:

The resulting phenol resin had a softening point of 78° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 1.2 dPa·s and a hydroxyl group equivalent of122 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 4, a C¹³ NMRchart is shown in FIG. 5 and an MS spectrum is shown in FIG. 6. GPCanalysis revealed that the content of a compound having a structurerepresented by “P—X—B” was 7% by mass and the content of a compoundhaving a structure represented by “B—X—B” was trace. As a result of themeasurement of the mass of the recovered unreacted phenol and2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 85/15. It was confirmed from a signal of amethoxy group observed at 55 ppm in NMR and a hydroxyl group equivalentthat the methoxy group in the compound is not decomposed. Also it couldbe confirmed that the resulting resin has a structure represented by“B—X—” at the molecular end.

Example 3 Synthesis of Phenol Resin (A-3)

In a flask equipped with a thermometer, a condenser tube, a distillingtube, and a stirrer, 141.2 g (1.50 mols) of phenol, 79.1 g (0.50 mols)of 2-methoxynaphthalene and 32.6 g (1.00 mols) of 92% paraformaldehydewere charged, mixed with 5.0 g of oxalic acid, reacted at 100° C. for 2hours by heating to 100° C. over one hour. After the completion of thereaction, 700 g of methyl isobutyl ketone was further added and thereaction solution was transferred to a separatory funnel, followed bywashing with water. After washing with water until rinse water showsneutrality, unreacted phenol, 2-methoxynaphthalene and methyl isobutylketone were removed from the organic layer with heating under reducedpressure to obtain 174 g of a phenol resin (A-3) having a structuralunit represented by the following structural formula:

The resulting phenol resin had a softening point of 74° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 1.0 dPa·s and a hydroxyl group equivalent of200 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 7. GPCanalysis revealed that the content of a compound having a structurerepresented by “P—X—B” was 22% by mass and the content of a compoundhaving a structure represented by “B—X—B” was 4% by mass. As a result ofthe measurement of the mass of the recovered unreacted phenol and2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 65/35. Also it could be confirmed that theresulting resin has a structure represented by “B—X—” at the molecularend.

Example 4 Synthesis of Phenol Resin (A-4)

In a flask equipped with a thermometer, a condenser tube, a distillingtube, a nitrogen introducing tube and a stirrer, 432.4 g (4.00 mols) ofo-cresol, 158.2 g (1.00 mols) of 2-methoxynaphthalene and 212.2 g (2.00mols) of benzaldehyde were charged, mixed with 9.0 g ofparatoluenesulfonic acid, reacted at 145° C. for 5 hours by heating to145° C. over one hour. While collecting water using a distilling tube,the reaction was conducted at 170° C. for 2 hours by heating to 170° C.over one hour. After the completion of the reaction, 1500 g of methylisobutyl ketone was further added and the reaction solution wastransferred to a separatory funnel, followed by washing with water.After washing with water until rinse water shows neutrality, unreactedo-cresol, 2-methoxynaphthalene and methyl isobutyl ketone were removedfrom the organic layer with heating under reduced pressure to obtain 545g of a phenol resin (A-4) having a structural unit represented by thefollowing structural formula:

The resulting phenol resin had a softening point of 99° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 5.0 dPa·s and a hydroxyl group equivalent of219 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 8. GPCanalysis revealed that the content of a compound having a structurerepresented by “P—X—B” was 12% by mass and the content of a compoundhaving a structure represented by “B—X—B” was 1% by mass. As a result ofthe measurement of the mass of the recovered unreacted o-cresol and2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 80/20. Also it could be confirmed that theresulting resin has a structure represented by “B—X—” at the molecularend.

Example 5 Synthesis of Phenol Resin (A-5)

In the same manner as in Example 3, except that 173.0 g (1.60 mols) ofphenol and 63.3 g (0.40 mols) of 2-methoxynaphthalene were used, 177 gof a phenol resin (A-5) having a structural unit represented by thefollowing structural formula:

was obtained. The resulting phenol resin had a softening point of 67° C.(B&R method), a melt viscosity (measuring method: ICI viscometer method,measured temperature: 150° C.) of 0.4 dPa·s and a hydroxyl groupequivalent of 170 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 9. GPCanalysis revealed that the content of a compound having a structurerepresented by “P—X—B” was 24% by mass and the content of a compoundhaving a structure represented by “B—X—B” was 3% by mass. As a result ofthe measurement of the mass of the recovered unreacted phenol and2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 74/26. Also it could be confirmed that theresulting resin has a structure represented by “B—X—” at the molecularend.

Example 6 Synthesis of Phenol Resin (A-6)

In the same manner as in Example 3, except that 334.0 g (1.67 mols) ofbisphenol F in place of the phenol in Example 3 and 131.3 g (0.83 mols)of 2-methoxynaphthalene were used, 350 g of a phenol resin (A-6) havinga structural unit represented by the following structural formula:

was obtained. The resulting phenol resin had a softening point of 64° C.(B&R method), a melt viscosity (measuring method: ICI viscometer method,measured temperature: 150° C.) of 0.5 dPa·s and a hydroxyl groupequivalent of 139 g/eq. A GPC chart of the resulting phenol resin isshown in FIG. 10. GPC analysis revealed that the content of a compoundhaving a structure represented by “P—X—B” was 0% by mass and the contentof a compound having a structure represented by “B—X—B” was 4% by mass.As a result of the measurement of the mass of the recovered unreacted2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 85/15. Also it could be confirmed that theresulting resin has a structure represented by “B—X—” at the molecularend.

Example 7 Synthesis of Phenol Resin (A-7)

In a flask equipped with a thermometer, a condenser tube, a distillingtube, a nitrogen introducing tube and a stirrer, 376.4 g (4.00 mols) ofphenol, 158.2 g (1.00 mols) of 2-methoxynaphthalene and 159.2 g (1.50mols) of benzaldehyde were charged, mixed with 9.0 g ofparatoluenesulfonic acid, reacted at 145° C. for 5 hours by heating to145° C. over one hour. While collecting water using a distilling tube,the reaction was conducted at 170° C. for 2 hours by heating to 170° C.over one hour. After the completion of the reaction, 1500 g of methylisobutyl ketone was further added and the reaction solution wastransferred to a separatory funnel, followed by washing with water.After washing with water until rinse water shows neutrality, unreactedphenol, 2-methoxynaphthalene and methyl isobutyl ketone were removedfrom the organic layer with heating under reduced pressure to obtain aphenol resin (A-7) having a structural unit represented by the followingstructural formula:

The resulting phenol resin had a softening point of 63° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 1.2 dPa·s and a hydroxyl group equivalent of288 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 11. As aresult of the measurement of the mass of the recovered unreacted phenoland 2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 80/20.

Example 8 Synthesis of Phenol Resin (A-8)

In the same manner as in Example 7, except that 182.2 g (1.00 mols) of4-biphenylaldehyde was used in place of benzaldehyde in Example 7, aphenol resin (A-8) having a structural unit represented by the followingstructural formula:

was obtained. The resulting phenol resin had a softening point of 61° C.(B&R method), a melt viscosity (measuring method: ICI viscometer method,measured temperature: 150° C.) of 1.1 dPa·s and a hydroxyl groupequivalent of 323 g/eq.

A GPC chart of the resulting phenol resin is shown in FIG. 12. As aresult of the measurement of the mass of the recovered unreacted phenoland 2-methoxynaphthalene and the measurement of a hydroxyl group of theresulting phenol resin, it was confirmed that a molar ratio of astructural unit of a phenolic hydroxyl group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the phenol resin, theformer/the latter, was 80/20.

Synthesis Example 1 Synthesis of Compound of Japanese Unexamined PatentApplication, First Publication No. 2004-010700

108.0 g (1.0 mols) of orthocresol and 132.0 g (2.2 mols) of an aqueous50% formalin solution were charged in a reaction vessel and 133.3 g (1.0mols) of an aqueous 30% sodium hydroxide solution was added dropwiseover one hour while maintaining at 30° C. or lower. After the completionof the dropwise addition, the reaction was conducted for 2 hours byheating to 40° C. Then, 126.0 g (1.0 mols) of dimethyl sulfate was addeddropwise at 40° C. over one hour and the reaction was conducted for 2hours by heating to 60° C., thereby to synthesize a resol resin whereina phenolic hydroxyl group is methoxylated. After the completion of thereaction, the aqueous layer was separated and 282.0 g (3.0 mols) ofphenol and 9.1 g of 35% hydrochloric acid were added, followed by thereaction at 90° C. for 4 hours. After the completion of the reaction,the reaction solution was neutralized with 6.0 g of an aqueous 25%ammonia solution and a neutralized salt was removed by washing withwater. The unreacted phenol was removed by heating to 200° C. under 60mmHg to obtain a phenol resin (A-9). The resulting phenol resin had asoftening point of 77° C. (B&R method), a melt viscosity (measuringmethod: ICI viscometer method, measured temperature: 150° C.) of 0.8dPa·s and a hydroxyl group equivalent of 160 g/eq.

Synthesis Example 2

In a 500 ml four-necked flask, 144 g (1.0 mols) of 2-naphthol, 200 g ofisopropyl alcohol and 8.2 g of 49% sodium hydroxide were charged andthen heated to 40° C. in a nitrogen gas flow while stirring. Afterheating, the temperature was raised to 60° C. while adding dropwise 37 g(0.5 mols) of 41% formalin over 2 hours and then the reaction wasconducted at 60° C. for 2 hours. As a result, a compound represented bythe following structural formula:

was obtained and a methylol compound was not obtained.

Example 9 Synthesis of Epoxy Resin (E-1)

In a flask equipped with a thermometer, a dropping funnel, a condensertube and a stirrer, 164 g (hydroxyl group: 1 equivalent) of the phenolresin (A-1) obtained in Example 1, 463 g (5.0 mols) of epichlorohydrin,139 g of n-butanol and 2 g of tetraethylbenzylammonium chloride werecharged and dissolved while purging with a nitrogen gas. After heatingto 65° C., the pressure was reduced to the pressure at which anazeotrope is produced, and then 90 g (1.1 mols) of an aqueous 49% sodiumhydroxide solution was added dropwise over 5 hours. Under the sameconditions, stirring was continued for 0.5 hours. The distillateproduced by azeotropy during stirring was separated by a Dean-Stark trapand the aqueous layer was removed, and then the reaction was conductedwhile returning the oil layer into the reaction system. Then, theunreacted epichlorohydrin was distilled off by distillation underreduced pressure. The resulting crude epoxy resin was dissolved in 590 gof methyl isobutyl ketone and 177 g of n-butanol. To the solution, 10 gof an aqueous 10% sodium hydroxide solution was added. After reacting at80° C. for 2 hours, the solution was repeatedly washed with 150 g ofwater three times until the pH of the wash becomes neutral. The systemwas dehydrated by azeotropy and, after precise filtration, the solventwas distilled off under reduced pressure to obtain 198 g of an epoxyresin (E-1) having a structural unit represented by the followingstructural formula.

The resulting epoxy resin had a softening point of 58° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 1.0 dPa·s and an epoxy equivalent of 252 g/eq.

A GPC chart of the resulting epoxy resin is shown in FIG. 13, a ¹³C NMRchart is shown in FIG. 14 and an MS spectrum is shown in FIG. 15. GPCanalysis revealed that the content of a compound having a structurerepresented by “E-X—B” was 10% by mass and the content of a compoundhaving a structure represented by “B—X—B” was 1% by mass. It wasconfirmed the remaining of methoxy group from a signal of a methoxygroup observed at 55 ppm in NMR and an epoxy equivalent that the methoxygroup in the compound is not decomposed. A molar ratio of a structuralunit of a glycidyloxy group-containing aromatic hydrocarbon group to astructural unit of an alkoxy group-containing condensed polycyclicaromatic hydrocarbon group in the epoxy resin was determined from theresults of the measurement of the mass of the recovered unreactedo-cresol and 2-methoxynaphthalene in case of producing the phenol resin(A-1) and the measurement of a hydroxyl group of the resulting phenolresin. As a result, a ratio of the former/the latter was 79/21. Also itcould be confirmed that the resulting resin has a structure representedby “B—X—” at the molecular end.

Example 10 Synthesis of Epoxy Resin (E-2)

In the same manner as in Example 9, except that the phenol resin (A-1)was replaced by 122 g (hydroxyl group: 1 equivalent) of the phenol resin(A-2) obtained in Example 2, 160 g of an epoxy resin (E-2) having astructural unit represented by the following structural formula:

was obtained by epoxidation reaction.

The resulting epoxy resin had a softening point of 60° C. (B&R method),a melt viscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 1.0 dPa·s and an epoxy equivalent of 200 g/eq.

A GPC chart of the resulting epoxy resin is shown in FIG. 16, a ¹³C NMRchart is shown in FIG. 17 and an MS spectrum is shown in FIG. 18. GPCanalysis revealed that the content of a compound having a structurerepresented by “E-X—B” was 6% by mass and the content of a compoundhaving a structure represented by “B—X—B” was trace. It was confirmedthe remaining of methoxy group from a signal of a methoxy group observedat 55 ppm in NMR and an epoxy equivalent that the methoxy group in thecompound is not decomposed. A molar ratio of a structural unit of aglycidyloxy group-containing aromatic hydrocarbon group to a structuralunit of an alkoxy group-containing condensed polycyclic aromatichydrocarbon group in the epoxy resin was determined from the results ofthe measurement of the mass of the recovered unreacted phenol and2-methoxynaphthalene in case of producing the phenol resin (A-2) and themeasurement of a hydroxyl group of the resulting phenol resin. As aresult, a ratio of the former/the latter was 92/8. Also it could beconfirmed that the resulting resin has a structure represented by “B—X—”at the molecular end.

Example 11 Synthesis of Epoxy Resin (E-3)

In the same manner as in Example 9, except that the phenol resin (A-1)was replaced by 200 g (hydroxyl group: 1 equivalent) of the phenol resin(A-3) obtained in Example 3, 230 g of an epoxy resin (E-3) having astructural unit represented by the following structural formula:

was obtained by epoxidation reaction. The resulting epoxy resin had asoftening point of 55° C. (B&R method), a melt viscosity (measuringmethod: ICI viscometer method, measured temperature: 150° C.) of 0.8dPa·s and an epoxy equivalent of 290 g/eq. A molar ratio of a structuralunit of a glycidyloxy group-containing aromatic hydrocarbon group to astructural unit of an alkoxy group-containing condensed polycyclicaromatic hydrocarbon group in the epoxy resin was determined from theresults of the measurement of the mass of the recovered unreacted phenoland 2-methoxynaphthalene in case of producing the phenol resin (A-3) andthe measurement of a hydroxyl group of the resulting phenol resin. As aresult, a ratio of the former/the latter was 65/35.

Example 12 Synthesis of Epoxy Resin (E-4)

In the same manner as in Example 9, except that the phenol resin (A-1)was replaced by 219 g (hydroxyl group: 1 equivalent) of the phenol resin(A-4) obtained in Example 4, 247 g of an epoxy resin (E-4) having astructural unit represented by the following structural formula:

was obtained by epoxidation reaction. The resulting epoxy resin had asoftening point of 78° C. (B&R method), a melt viscosity (measuringmethod: ICI viscometer method, measured temperature: 150° C.) of 2.0dPa·s and an epoxy equivalent of 298 g/eq.

A GPC chart of the resulting epoxy resin is shown in FIG. 19. GPCanalysis revealed that the content of a compound having a structurerepresented by “E-X—B” was 11% by mass and the content of a compoundhaving a structure represented by “B—X—B” was 1% by mass. A molar ratioof a structural unit of a glycidyloxy group-containing aromatichydrocarbon group to a structural unit of an alkoxy group-containingcondensed polycyclic aromatic hydrocarbon group in the epoxy resin wasdetermined from the results of the measurement of the mass of therecovered unreacted o-cresol and 2-methoxynaphthalene in case ofproducing the phenol resin (A-4) and the measurement of a hydroxyl groupof the resulting phenol resin. As a result, a ratio of the former/thelatter was 80/20. Also it could be confirmed that the resulting resinhas a structure represented by “B—X—” at the molecular end.

Synthesis Example 3

In a flask equipped with a thermometer, a dropping funnel, a condensertube and a stirrer, 168 parts of Milex XLC-4L manufactured by MitsuiChemicals Co., Ltd., 463 g (5.0 mols) of epichlorohydrin, 139 g ofn-butanol and 2 g of tetraethylbenzylammonium chloride were charged anddissolved while purging with a nitrogen gas. After heating to 65° C.,the pressure was reduced to the pressure at which an azeotrope isproduced, and then 90 g (1.1 mols) of an aqueous 49% sodium hydroxidesolution was added dropwise over 5 hours. Under the same conditions,stirring was continued for 0.5 hours. The distillate produced byazeotropy during stirring was separated by a Dean-Stark trap and theaqueous layer was removed, and then the reaction was conducted whilereturning the oil layer into the reaction system. Then, the unreactedepichlorohydrin was distilled off by distillation under reducedpressure. The resulting crude epoxy resin was dissolved in 590 g ofmethyl isobutyl ketone and 177 g of n-butanol. To the solution, 10 g ofan aqueous 10% sodium hydroxide solution was added. After reacting at80° C. for 2 hours, the solution was repeatedly washed with 150 g ofwater three times until the pH of the wash becomes neutral. The systemwas dehydrated by azeotropy and, after precise filtration, the solventwas distilled off under reduced pressure to obtain an epoxy resin (E-5)having a structural unit represented by the following structuralformula.

The resulting epoxy resin had an epoxy equivalent of 241 g/eq.

Synthesis Example 4 Synthesis of Epoxy Resin Described in JapaneseUnexamined Patent Application, First Publication No. 2003-201333

In a 1 liter four-necked flask equipped with a stirrer and a heater, 152g (1.0 mols) of trimethylhydroquinone was dissolved in a solvent mixtureof 500 g of toluene and 200 g of ethylene glycol monoethyl ether. To thesolution, 4.6 g of paratoluenesulfonic acid was added and 64 g (0.6mols) of 41% benzaldehyde was added dropwise while paying attention toheat generation. While distilled off moisture, the solution was stirredat 100 to 120° C. for 15 hours. After cooling, the precipitated crystalwas collected by filtration, repeatedly washed with water until thefiltrate becomes neutral, and then dried to obtain 175 g of a phenolresin (GPC purity: 99%).

In a flask equipped with a thermometer, a dropping funnel, a condensertube and a stirrer, 175 g of a phenol resin, 463 g (5.0 mols) ofepichlorohydrin, 53 g of n-butanol and 2.3 g of tetraethylbenzylammoniumchloride were charged and dissolved while purging with a nitrogen gas.After heating to 65° C., the pressure was reduced to the pressure atwhich an azeotrope is produced, and then 82 g (1.0 mols) of an aqueous49% sodium hydroxide solution was added dropwise over 5 hours. Under thesame conditions, stirring was continued for 0.5 hours.

The distillate produced by azeotropy during stirring was separated by aDean-Stark trap and the aqueous layer was removed, and then the reactionwas conducted while returning the oil layer into the reaction system.Then, the unreacted epichlorohydrin was distilled off by distillationunder reduced pressure. The resulting crude epoxy resin was dissolved in550 g of methyl isobutyl ketone and 55 g of n-butanol. To the solution,15 g of an aqueous 10% sodium hydroxide solution was added. Afterreacting at 80° C. for 2 hours, the solution was repeatedly washed with100 g of water three times until the pH of the wash becomes neutral. Thesystem was dehydrated by azeotropy and, after precise filtration, thesolvent was distilled off under reduced pressure to obtain an epoxyresin (E-6) represented by the following structural formula.

The resulting epoxy resin had an epoxy equivalent of 262 g/eq.

Synthesis Example 4 Synthesis of Compound of Japanese Unexamined PatentApplication, First Publication No. Hei 8-301980

In a 500 ml four-necked flask, 166 g (1.0 mols) of p-xylylene glycoldimethyl ether, 42.5 g (0.25 mols) of diphenyl ether and 12.5 g ofp-toluenesulfonic acid were charged and then reacted in a nitrogen gasflow at 150° C. while stirring. Methanol produced during the reactionwas removed out of the system. After about 3 hours, when 16 g ofmethanol was produced, 202.5 g (1.88 mols) of o-cresol was added and thereaction was further conducted at 150° C. for 2 hours. Subsequently,methanol produced during the reaction was removed out of the system.After the completion of the production of methanol, the reactionsolution was neutralized with sodium carbonate and excess o-cresol wasdistilled off to obtain 237.5 g of a phenol resin (B-10). The resultingphenol resin had a softening point of 100° C. (B&R method), a meltviscosity (measuring method: ICI viscometer method, measuredtemperature: 150° C.) of 19 dPa·s and a hydroxyl group equivalent of 249g/eq.

In the same manner as in Example 9, except that 249 g/eq (hydroxylgroup: 1 equivalent) of a phenol resin obtained by the above method wasused in place of the phenol resin (A-1), the epoxydation reaction wascarried out to obtain an epoxy resin (E-7). The resulting epoxy resinhad a softening point of 79° C. (B&R method) and an epoxy equivalent of421 g/eq.

Examples 13 to 31 and Comparative Examples 1 to 3

Using the above epoxy resins (E-1) to (E-6), YX-4000H (tetramethylbiphenol type epoxy resin, epoxy equivalent: 195 g/eq) manufactured byJapan Epoxy Resins Co., Ltd., NC-3000 (biphenyl novolak type epoxyresin, epoxy equivalent: 274 g/eq) manufactured by Nippon Kayaku Co.,Ltd. and EXA-4700 (naphthalene type epoxy resin, epoxy equivalent: 164g/eq) manufactured by DAINIPPON INK & CHEMICALS Co., Ltd. as the epoxyresin; the avove phenol resins (A-1) to (A-8), XLC-LL (phenol aralkylresin, hydroxyl group equivalent: 176 g/eq) manufactured by MitsuiChemicals Co., Ltd. and MEH-7851SS (biphenyl novolak resin, hydroxylgroup equivalent: 200 g/eq) manufactured by Meiwa Plastic Industries,Ltd. as the phenol resin; a comparative epoxy resin E-7; a comparativephenol resin A-9; triphenylphosphine (TPP) as the curing accelerator;condensed phosphate ester (PX-200, manufactured by Daihachi ChemicalIndustry Co., Ltd.) and magnesium hydroxide (Echomag Z-10, manufacturedby Air Water Inc.) as the flame retardant; spherical silica (S-COL,manufactured by Micron Co., Ltd.) as the inorganic filler;γ-glycidoxytriethoxysilane (KBM-403, manufactured by SHIN-ETSU CHEMICALCO., LTD.) as the silane coupling agent; carnauba wax (PEARL WAX No.1-P, manufactured by Cerarica Noda Co. Ltd.); and carbon black accordingto the formulations shown in Tables 1 to 3, these components weremelt-kneaded at a temperature of 85° C. for 5 minutes using a twin rollto obtain the objective compositions, and then curability was evaluated.Physical properties of the cured article were evaluated by the followingprocedure. That is, samples for evaluation were produced by thefollowing method using the above compositions, and then heat resistance,flame retardancy and dielectric characteristics were determined by thefollowing method. The results are shown in Tables 1 to 2.

<Heat Resistance>

Glass transition temperature was measured using a viscoelasticitymeasuring apparatus (solid viscoelasticity measuring apparatus RSAIImanufactured by Rheometric Co., double cantilever method; frequency: 1Hz, temperature raising rate: 3° C./min).

<Curability>

0.15 g of each epoxy resin composition was placed on a cure plate(manufactured by THERMO ELECTRIC Co., Ltd.) heated to 175° C. and timemeasurement was initiated using a stop watch. The sample was uniformlystirred using a bar. When it became possible to cut the sample into theform of string and they were remained on the plate, the stop watch wasstopped. The time required for the sample to be cut and remained on theplate was taken as a gel time.

<Flame Retardancy>

Samples for evaluation, each measuring 12.7 mm in width, 127 mm inlength and 1.6 mm in thickness were obtained by molding at a temperatureof 175° C. for 90 seconds using a transfer molding machine and by curingat a temperature of 175° C. for 5 hours. Using 5 test samples having athickness of 1.6 mm thus obtained, a combustion test was conducted inaccordance with a UL-94 test method.

<Measurement of Dielectric Characteristics>

Samples for evaluation, each measuring 25 mm in width, 75 mm in lengthand 2.0 mm in thickness were obtained by molding at a temperature of175° C. for 90 seconds using a transfer molding machine and curing at atemperature of 175° C. for 5 hours. Each of test samples thus obtainedwas bone-dried and then stored in a room at 23° C. and a humidity of 50%for 24 hours to obtain a cured article. The dielectric constant anddielectric dissipation factor at a frequency of MHz of the resultingcured article were measured by a method defined in JIS-C-6481 using animpedance material analyzer “HP4291B” manufactured by Agilent TechnologyCo., Ltd.

TABLE 1 Formulation of epoxy resin composition (parts by mass) andevaluation results Examples 13 14 15 16 17 18 19 20 21 22 Epoxy E-1 7975 E-2 71 72 67 66 E-3 83 84 83 E-4 84 Curing agent A-5 62 50 XLC-LL 5563 51 50 51 58 MEH-7851SS 59 67 Condensed phosphate ester 30 Magnesiumhydroxide 30 30 TPP 3 3 3 3 3 3 3 3 3 3 Fused silica 850 850 850 850 850850 850 820 820 830 Coupling agent 5 5 5 5 5 5 5 5 5 5 Carnauba wax 5 55 5 5 5 5 5 5 5 Carbon black 3 3 3 3 3 3 3 3 3 3 Curability 25 38 20 2731 33 35 28 29 20 Heat resistance 132 122 151 133 144 128 126 141 144134 Class of combustion test V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 1*4 3 5 4 5 4 7 4 3 3 2* 18 14 23 18 21 16 24 16 13 11 Dielectric constant2.87 2.85 2.98 2.91 2.87 2.80 2.84 2.98 2.91 3.03 Dielectric dissipationfactor (×10⁻⁴) 75 70 96 85 75 61 64 98 92 100

TABLE 2 Formulation of epoxy resin composition (parts by mass) andevaluation results Examples 23 24 25 26 27 28 29 30 31 Epoxy E-2 E-3 5854 57 E-5 24 61 73 46 61 57 E-6 25 NC-3000 YX-4000H 19 20 EXA-4700 23 43Curing agent A-3 61 72 58 A-5 43 A-7 73 A-8 77 XLC-LL 52 57 53MEH-7851SS Condensed phosphate ester Magnesium hydroxide 30 TPP 3 3 3 33 3 3 3 3 Fused silica 850 850 850 820 850 850 850 850 820 Couplingagent 5 5 5 5 5 5 5 5 5 Carnauba wax 5 5 5 5 5 5 5 5 5 Carbon black 3 33 3 3 3 3 3 3 Curability 34 26 28 23 26 22 31 37 39 Heat resistance 157164 133 127 120 161 122 128 125 Class of combustion test V-0 V-0 V-0 V-0V-0 V-0 V-0 V-0 V-0 1* 6 6 6 6 5 4 7 3 3 2* 26 31 29 25 23 20 36 15 13Dielectric constant 2.89 3.01 2.92 2.89 2.98 2.96 2.88 2.83 2.80Dielectric dissipation factor (×10⁻⁴) 93 87 87 81 87 85 84 64 61 Notesof Tables 1 and 2: *1: Maximum flame maintenance time for a single flamecontact (seconds) *2: Total flame maintenance time of 5 test samples(seconds)

TABLE 3 Formulation of epoxy resin composition (parts by mass) andevaluation results Comparative Examples 1 2 3 Epoxy E-5 81 E-7 94NC-3000 85 Curing agent A-9 49 53 XLC-LL 40 TPP 3 3 3 Fused silica 850850 850 Coupling agent 5 5 5 Carnauba wax 5 5 5 Carbon black 3 3 3Curability 50 47 54 Heat resistance 120 131 125 Class of combustion testV-1 V-1 *3 1* 18 23 37 2* 107 146 143 Dielectric constant 3.05 3.14 3.27Dielectric dissipation factor (×10⁻⁴) 103 125 135 Notes of Table 3: *1:Maximum flame maintenance time for a single flame contact (seconds) *2:Total flame maintenance time of 5 test samples (seconds) *3: Samples donot satisfy flame retardancy (ΣF ≦ 250 seconds and F_(max) ≦ 30 seconds)required for V-1, but none of samples shows any ignition (arrival offlame at a clamp) while all resulted in extinction.

INDUSTRIAL APPLICABILITY

According to the present invention, there can be provided an epoxy resincomposition capable of realizing low dielectric constant and lowdielectric dissipation factor, which is suited for use as a latesthigh-frequency type electronic component-related material, whilemaintaining excellent heat resistance of a cured article thereof, and acured article thereof, a novel phenol resin which imparts theseperformances, and a novel epoxy resin.

1. An epoxy resin composition, comprising an epoxy resin and a curingagent as essential components, wherein the curing agent is a phenolresin which has respective structural units of: a phenolic hydroxylgroup-containing aromatic hydrocarbon group (P), an alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B),and a divalent hydrocarbon group (X) selected from methylene, analkylidene group and an aromatic hydrocarbon structure-containingmethylene group, and the phenol resin has, in a molecular structure, astructure in which the phenolic hydroxyl group-containing aromatichydrocarbon group (P) and the alkoxy group-containing condensedpolycyclic aromatic hydrocarbon group (B) are bonded via the divalenthydrocarbon group (X) selected from methylene, the alkylidene group andthe aromatic hydrocarbon structure-containing methylene group.
 2. Theepoxy resin composition according to claim 1, wherein the phenol resinhas, at a molecular end, a structural unit represented by the followingstructural formula:B—X—  [Chemical Formula 1] wherein B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B),and X is a structural unit of the divalent hydrocarbon group (X)selected from methylene, the alkylidene group and the aromatichydrocarbon structure-containing methylene group.
 3. The epoxy resincomposition according to claim 1, wherein the phenol resin has a meltviscosity at 150° C., as measured by an ICI viscometer, of 0.1 to 5.0dPa·s.
 4. The epoxy resin composition according to claim 1, wherein thephenol resin contains a compound having a structure represented by thefollowing structural formula:P—X—B  [Chemical Formula 2] wherein P is a structural unit of thephenolic hydroxyl group-containing aromatic hydrocarbon group (P), B isa structural unit of the alkoxy group-containing condensed polycyclicaromatic hydrocarbon group (B) and X is a structural unit of thedivalent hydrocarbon group (X) selected from methylene, the alkylidenegroup and the aromatic hydrocarbon structure-containing methylene group,the content of the compound in the phenol resin being 1 to 30% by mass.5. The epoxy resin composition according to claim 1, wherein the phenolresin is obtained by reacting a hydroxy group-containing aromaticcompound (a1), an alkoxy group-containing condensed polycyclic aromaticcompound (a2) and a carbonyl group-containing compound (a3), and thecontent of a compound represented by the following structural formula:B—X—B  [Chemical Formula 3] wherein B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the divalent hydrocarbon group (X) selectedfrom methylene, the alkylidene group and the aromatic hydrocarbonstructure-containing methylene group, in the phenol resin is 5% by massor less.
 6. An epoxy resin cured article obtained by curing the epoxyresin composition according to any one of claims 1 to
 5. 7. Asemiconductor encapsulation material comprising the epoxy resincomposition according to any one of claims 1 to 5 which furthercontains, in addition to the epoxy resin and the curing agent, aninorganic filler within a range of 70 to 95% by mass with respect to theepoxy resin composition.
 8. A novel phenol resin, including respectivestructural units of: a phenolic hydroxyl group-containing aromatichydrocarbon group (P), an alkoxy group-containing condensed polycyclicaromatic hydrocarbon group (B), and a divalent hydrocarbon group (X)selected from methylene, an alkylidene group and an aromatic hydrocarbonstructure-containing methylene group, wherein the phenol resin has, in amolecular structure, a structure in which the phenolic hydroxylgroup-containing aromatic hydrocarbon group (P) and the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) arebonded via the alkylidene group (X), and the phenol resin has a meltviscosity at 150° C., as measured by an ICI viscometer, of 0.1 to 5.0dPa·s and a hydroxyl group equivalent of 120 to 500 g/eq.
 9. An epoxyresin composition, comprising an epoxy resin and a curing agent asessential components, wherein the epoxy resin has respective structuralunits of: a glycidyloxy group-containing aromatic hydrocarbon group (E),an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and a divalent hydrocarbon group (X) selected from methylene,an alkylidene group and an aromatic hydrocarbon structure-containingmethylene group, and the epoxy resin has, in a molecular structure, astructure in which the glycidyloxy group-containing aromatic hydrocarbongroup (E) and the alkoxy group-containing condensed polycyclic aromatichydrocarbon group (B) are bonded via the divalent hydrocarbon group (X)selected from methylene, the alkylidene group and the aromatichydrocarbon structure-containing methylene group.
 10. The epoxy resincomposition according to claim 9, wherein the epoxy resin has, at amolecular end, a structural unit represented by the following structuralformula:B—X—  [Chemical Formula 1] wherein B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the divalent hydrocarbon group (X) selectedfrom methylene, the alkylidene group and the aromatic hydrocarbonstructure-containing methylene group.
 11. The epoxy resin compositionaccording to claim 9, wherein the epoxy resin has a melt viscosity at150° C. of 0.1 to 5.0 dPa·s.
 12. The epoxy resin composition accordingto claim 9, wherein the epoxy resin contains a compound having astructure represented by the following structural formula:E-X—B  [Chemical Formula 4] wherein E is a structural unit of theglycidyloxy group-containing aromatic hydrocarbon group (E), B is astructural unit of the alkoxy group-containing condensed polycyclicaromatic hydrocarbon group (B) and X is a structural unit of thedivalent hydrocarbon group (X) selected from methylene, the alkylidenegroup and the aromatic hydrocarbon structure-containing methylene group,the content of the compound in the epoxy resin being 1 to 30% by mass.13. The epoxy resin composition according to claim 9, wherein the epoxyresin is obtained by reacting a phenol resin, which is obtained byreacting a hydroxy group-containing aromatic compound (a1), an alkoxygroup-containing condensed polycyclic aromatic compound (a2) and acarbonyl group-containing compound (a3), with epihalohydrin, and thecontent of a compound represented by the following structural formula:B—X—B  [Chemical Formula 3] wherein B is a structural unit of the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) andX is a structural unit of the divalent hydrocarbon group (X) selectedfrom methylene, the alkylidene group and the aromatic hydrocarbonstructure-containing methylene group, in the epoxy resin is 5% by massor less.
 14. The epoxy resin composition according to claim 9, whereinthe curing agent is a phenol resin which has respective structural unitsof: a phenolic hydroxyl group-containing aromatic hydrocarbon group (P),an alkoxy group-containing condensed polycyclic aromatic hydrocarbongroup (B), and a divalent hydrocarbon group (X) selected from methylene,an alkylidene group and an aromatic hydrocarbon structure-containingmethylene group, and the phenol resin has, in a molecular structure, astructure in which the phenolic hydroxyl group-containing aromatichydrocarbon group (P) and the alkoxy group-containing condensedpolycyclic aromatic hydrocarbon group (B) are bonded via the alkylidenegroup (X).
 15. An epoxy resin cured article obtained by curing the epoxyresin composition according to any one of claims 9 to
 14. 16. Asemiconductor encapsulation material, comprising the epoxy resincomposition according to any one of claims 9 to 14 which furthercontains, in addition to the epoxy resin and the curing agent, aninorganic filler within a range of 70 to 95% by mass with respect to theepoxy resin composition.
 17. A novel epoxy resin, including respectivestructural units of: a glycidyloxy group-containing aromatic hydrocarbongroup (E), an alkoxy group-containing condensed polycyclic aromatichydrocarbon group (B), and a divalent hydrocarbon group (X) selectedfrom methylene, an alkylidene group and an aromatic hydrocarbonstructure-containing methylene group, wherein the epoxy resin has, in amolecular structure, a structure in which the glycidyloxygroup-containing aromatic hydrocarbon group (E) and the alkoxygroup-containing condensed polycyclic aromatic hydrocarbon group (B) arebonded via the alkylidene group (X), and the epoxy resin has a meltviscosity at 150° C., measured by an ICI viscometer, of 0.1 to 5.0 dPa·sand an epoxy group equivalent of 200 to 500 g/eq.